U.S. patent application number 17/717571 was filed with the patent office on 2022-07-28 for systems and methods for asymmetrical digital prefix transmissions.
The applicant listed for this patent is Cable Television Laboratories, Inc.. Invention is credited to Luis Alberto Campos, Douglas D. Jones, Thomas Holtzman Williams.
Application Number | 20220239537 17/717571 |
Document ID | / |
Family ID | 1000006259814 |
Filed Date | 2022-07-28 |
United States Patent
Application |
20220239537 |
Kind Code |
A1 |
Jones; Douglas D. ; et
al. |
July 28, 2022 |
SYSTEMS AND METHODS FOR ASYMMETRICAL DIGITAL PREFIX
TRANSMISSIONS
Abstract
A method for transmitting a digital frame by an optical network
unit in a digital communications network includes steps of
arranging received data into a series of symbols, installing a
primary cyclic prefix immediately preceding the series of symbols
in time, and inserting individual ones of a plurality of secondary
cyclic prefixes between each adjacent pair of symbols in the series
of symbols. A length of each secondary cyclic prefix corresponds to
a first duration shorter than an amount of time needed to turn on a
laser of the optical network unit. The method further includes a
step of providing to the optical network unit the digital frame.
The digital frame includes the primary cyclic prefix, the plurality
of secondary cyclic prefixes, and the series of symbols. The method
further includes a step of modulating the provided digital frame by
a laser of the optical network unit.
Inventors: |
Jones; Douglas D.; (Boulder,
CO) ; Campos; Luis Alberto; (Superior, CO) ;
Williams; Thomas Holtzman; (Longmont, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cable Television Laboratories, Inc. |
Louisville |
CO |
US |
|
|
Family ID: |
1000006259814 |
Appl. No.: |
17/717571 |
Filed: |
April 11, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16806969 |
Mar 2, 2020 |
11303486 |
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17717571 |
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16041415 |
Jul 20, 2018 |
10581654 |
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16806969 |
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62534945 |
Jul 20, 2017 |
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62534953 |
Jul 20, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 27/2607 20130101;
H04B 10/548 20130101; H04L 5/0048 20130101; H04L 27/2697 20130101;
H04Q 11/0067 20130101; H04B 10/27 20130101; H04Q 2011/0088
20130101; H04L 27/2608 20130101 |
International
Class: |
H04L 27/26 20060101
H04L027/26; H04Q 11/00 20060101 H04Q011/00; H04B 10/27 20060101
H04B010/27; H04L 5/00 20060101 H04L005/00; H04B 10/548 20060101
H04B010/548 |
Claims
1. A receiver for a digital transmission system, comprising: a
processing unit configured to receive a modulated digital data
signal and generate at least one data frame therefrom, the at least
one data frame including: (a) a series of data blocks; (b) a
primary data prefix for the series of data blocks; and (c) first
and second secondary data prefixes disposed between adjacent data
blocks within the series of data blocks, wherein each of the first
and second secondary data prefixes has a shorter duration length
than the primary data prefix.
2. The receiver of claim 1, further comprising a modem in operable
communication with the processing unit, wherein the modem is
configured to transmit the at least one data frame onto a digital
communication medium in operable communication with the modem.
3. The receiver of claim 2, further comprising a media access
control (MAC) layer.
4. The receiver of claim 2, wherein the digital communication
medium includes wireless transport media.
5. The receiver of claim 2, wherein the digital communication
medium includes wired transport media.
6. The receiver of claim 5, wherein the wired transport media
includes at least one optical fiber.
7. The receiver of claim 6, wherein the at least one optical fiber
is in operable communication with a laser, and wherein the duration
length of each of the first and second secondary prefixes is
shorter than a turn-on time for the laser.
8. A receiver for a digital transmission network, comprising: a
processor in operable communication with a memory, wherein the
processor is configured to receive a digital data transmission from
the digital transmission network and output at least one digital
data frame having a frame architecture including: a series of data
blocks; a primary data prefix preceding the series of data blocks
in time; and first and second secondary data prefixes respectively
disposed between adjacent pairs of data blocks within the series of
data blocks following the primary data prefix.
9. The receiver of claim 8, wherein the at least one digital data
frame is an orthogonal frequency-division multiple access (OFDMA)
frame including a plurality of OFDMA symbols.
10. The receiver of claim 9, wherein each data block of the series
of data blocks includes at least one OFDMA symbol.
11. The receiver of claim 9, wherein the OFDMA frame corresponds to
a data over cable service interface specification (DOCSIS)
format.
12. The receiver of claim 9, wherein a length of the primary data
prefix is longer than a length of each of the first and second
secondary data prefixes.
13. The receiver of claim 9, wherein a length of the primary data
prefix is substantially twice a length of at least one of the first
and second secondary data prefixes.
14. The receiver of claim 9, wherein a length of the primary data
prefix is substantially the same as a length of each of the first
and second secondary data prefixes.
15. The receiver of claim 14, wherein the at least one digital data
frame is configured such that a continuous wave tone immediately
precedes the primary data prefix.
16. A digital transmission receiver, comprising: a processor
configured to receive digital data and generate at least one data
frame therefrom for an output modulated digital signal; and a
memory in operable communication with the processor, the memory
being configured to store therein computer-executable instructions,
which, when executed by the processor, cause the processor to
structure the at least one data frame into a frame architecture,
comprising: a series of data blocks; a primary data prefix
preceding the series of data blocks in time; and first and second
secondary data prefixes respectively disposed between adjacent
pairs of data blocks within the series of data blocks, wherein a
length of each of the first and second secondary data prefixes is
shorter than a length of the primary data prefix.
17. The receivers of claim 16, wherein the at least one digital
data frame is an orthogonal frequency-division multiple access
(OFDMA) frame including a plurality of OFDMA symbols.
18. The digital transmission apparatus of claim 17, wherein each
data block of the series of data blocks includes at least one OFDMA
symbol corresponding to a data over cable service interface
specification (DOCSIS) format.
19. The digital transmission apparatus of claim 17, wherein the
length of the primary data prefix is substantially twice the length
of each of the first and second secondary data prefixes.
20. The digital transmission apparatus of claim 16, wherein the
instructions further cause the processor to structure the at least
one digital data frame such that a continuous wave tone immediately
precedes the primary data prefix.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 16/806,969, filed Mar. 2, 2020. U.S. application Ser. No.
16/806,969 is a continuation of U.S. application Ser. No.
16/041,415, filed Jul. 20, 2018, now U.S. Pat. No. 10,581,654,
which prior application claims the benefit of and priority to U.S.
Provisional Patent Application Ser. No. 62/534,945, filed Jul. 20,
2017, and to U.S. Provisional Patent Application Ser. No.
62/534,953, filed Jul. 20, 2017, the disclosures of which are
herein incorporated by reference in their entireties.
BACKGROUND
[0002] The field of the disclosure relates generally to digital
transmission systems, and more particularly, to multi-carrier
wired, wireless, and optical digital transmission systems utilizing
cyclic prefixes.
[0003] Conventional digital transmission systems typically include
both linear and non-linear distortion. However, for the purposes of
the following discussion, use of the term "distortion" is generally
intended to refer to linear distortion only. Some conventional
digital transmission systems utilize orthogonal frequency division
multiplexing (OFDM) and orthogonal frequency division multiple
access (OFDMA) techniques for transmitting carrier signals using
technology such as the Data Over Cable Service Interface
Specification (DOCSIS), or DOCSIS version 3.1, as well as other
wireless standards. OFDM implements a plurality of different
subcarriers that are harmonics of a fundamental to obtain
orthogonality. DOCSIS specifications typically utilize OFDM for
downstream signals and OFDMA for upstream signals, and OFDM and
OFDMA are complimentary.
[0004] One type of conventional digital transmission system is
Radio Frequency over Glass (RFoG). RFoG is defined by the Society
of Cable Telecommunications Engineers (SCTE) in SCTE 174, and
transmits DOCSIS RF signals to a home, or customer premises, over
fiber optics. RFoG allows cable operators to use existing Modem
Termination Systems (MTS) to transmit RF over a passive optical
network (PON) architecture to a modem (e.g., an optical network
unit (ONU), a cable modem (CM), etc.), at the home/customer
premises. The fiber optic transmission lines used in RFoG provide
greater downstream and upstream bandwidth than then conventional
coaxial cables. RFoG typically reduces operational expenses by
allowing the substitution of passive components (e.g., splitters)
for active components (e.g. amplifiers), thereby reducing the power
requirements for the system, but also the reach of the system.
[0005] Both OFDM and OFDMA are known to use cyclic prefixes (CPs)
in the data blocks of a transmitted digital signal. The cyclic
prefix functions as a "guard time" that separates data bursts, and
that allows any micro-reflection from one burst to die out before
the next burst is received, thereby eliminating interference from
one block to the next. CPs are commonly used in hybrid fiber
coaxial (HFC) networks, where reflections are frequently known to
occur, and various durations of CPs are utilized to accommodate the
variety of reflections that may occur therein, thereby
significantly increasing the overhead of the HFC network, because
the CPs do not carry useful customer information (i.e., customer
data). The CPs provide block-to-block isolation between the data
block bursts of digital information, but CPs require additional
resources to transmit the extra data that constitutes the CP. Such
required CP data reduces the bandwidth efficiency of transmissions,
thereby limiting the amount of data that can be transmitted within
a given frequency band, while also requiring additional power and
decreasing the battery life of system components.
[0006] DOC SIS 3.1 transmissions over an HFC network utilize a
single value for an upstream CP, and the length of this single
value CP is set to accommodate the longest micro-reflection that
will be observed on the coaxial cable(s) of the HFC network. DOCSIS
3.1 transmissions over an RFoG network, on the other hand, require
that the CP length is set long enough to activate an ONU laser of
the RFoG network (sometimes referred to as an R-ONU). The RFoG ONU
is typically located at the customer premises, and serves as the
transport layer for RF video, voice, and DOCSIS technologies in
deep fiber and fiber-to-the-home (FTTH) access networks. In many
instances, the ONU also functions as or substitutes for a modem/CM.
As defined in SCTE 174, where the upstream RFoG ONU laser requires
1.3 microseconds (.mu.s) to activate and stabilize (the ONU is
"always-on" downstream), upstream DOCSIS 3.1 transmissions over a
RFoG network requires the upstream cyclic prefix to be greater than
1.3 .mu.s, for the first symbol, to activate and stabilize the ONU
laser. That is, within 1.3 .mu.s, the RFoG ONU should reach and
maintain steady-state stability upon turn-on.
[0007] FIG. 1 illustrates a timing diagram 100 for a conventional
data burst 102 in an RFoG ONU. Timing diagram 100 depicts turn-on
and turn-off durations of burst 102 such that a cyclic prefix (not
shown) is generated to be long enough to accommodate the duration
T1 of the leading edge of burst 102 (i.e., 1.3 .mu.s). The T1 thus
corresponds to the maximum time after application of a valid
turn-on of the RF input in which an optical modulator of the ONU
should achieve and maintain RF signal level stability within
.+-.0.1 dB (e.g., observed at the output of a reference
optical-to-electrical converter, not shown). The T1 duration is
also considered sufficient to reach and maintain performance
requirements of the noise power ratio (NPR). However, this large of
and upstream CP length is wasteful of upstream transmission
capacity, since the length is determined by the amount of time
needed to turn-on the RFoG ONU in the first burst, but which is not
needed in subsequent bursts when the ONU is already on.
BRIEF SUMMARY
[0008] In an embodiment, a method is provided for transmitting a
digital frame by an optical network unit in a digital
communications network. The method includes steps of arranging
received data into a series of symbols, installing a primary cyclic
prefix immediately preceding the series of symbols in time, and
inserting individual ones of a plurality of secondary cyclic
prefixes between each adjacent pair of symbols in the series of
symbols. A length of each secondary cyclic prefix corresponds to a
first duration shorter than an amount of time needed to turn on a
laser of the optical network unit. The method further includes a
step of providing to the optical network unit the digital frame.
The digital frame includes the primary cyclic prefix, the plurality
of secondary cyclic prefixes, and the series of symbols. The method
further includes a step of modulating the provided digital frame by
a laser of the optical network unit.
[0009] In an embodiment, an optical network unit (ONU) for a
digital transmission system is provided. The ONU includes an input
portion configured to receive digital data, a processor configured
to form the received digital data at least one data frame including
a series of data blocks, a laser configured to modulate the at
least one data frame is a digital signal for transmission over the
digital transmission system, and a modem portion in operable
communication with the processor and the laser, and configured to
transmit the at least one data frame to the digital transmission
system The at least one data frame further includes a primary
cyclic prefix preceding the series of data blocks and a plurality
of secondary cyclic prefixes each respectively disposed between
adjacent ones of the series of data blocks. A length of each of the
secondary cyclic prefixes has a shorter duration than an amount of
time needed to turn on the laser.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] These and other features, aspects, and advantages of the
present disclosure will become better understood when the following
detailed description is read with reference to the following
accompanying drawings, in which like characters represent like
parts throughout the drawings.
[0011] FIG. 1 illustrates a timing diagram for a conventional data
burst in an RFoG ONU.
[0012] FIG. 2 is a schematic illustration depicting an exemplary
data structure of an OFDMA frame, according to an embodiment.
[0013] FIG. 3 is a schematic illustration depicting an exemplary
data structure of an OFDMA frame, according to an alternative
embodiment.
[0014] Unless otherwise indicated, the drawings provided herein are
meant to illustrate features of embodiments of this disclosure.
These features are believed to be applicable in a wide variety of
systems including one or more embodiments of this disclosure. As
such, the drawings are not meant to include all conventional
features known by those of ordinary skill in the art to be required
for the practice of the embodiments disclosed herein.
DETAILED DESCRIPTION
[0015] In the following specification and the claims, reference
will be made to a number of terms, which shall be defined to have
the following meanings.
[0016] The singular forms "a," "an," and "the" include plural
references unless the context clearly dictates otherwise.
[0017] "Optional" or "optionally" means that the subsequently
described event or circumstance may or may not occur, and that the
description includes instances where the event occurs and instances
where it does not.
[0018] Approximating language, as used herein throughout the
specification and claims, may be applied to modify any quantitative
representation that could permissibly vary without resulting in a
change in the basic function to which it is related. Accordingly, a
value modified by a term or terms, such as "about,"
"approximately," and "substantially," are not to be limited to the
precise value specified. In at least some instances, the
approximating language may correspond to the precision of an
instrument for measuring the value. Here and throughout the
specification and claims, range limitations may be combined and/or
interchanged; such ranges are identified and include all the
sub-ranges contained therein unless context or language indicates
otherwise.
[0019] As used herein, the terms "processor" and "computer" and
related terms, e.g., "processing device", "computing device", and
"controller" are not limited to just those integrated circuits
referred to in the art as a computer, but broadly refers to a
microcontroller, a microcomputer, a programmable logic controller
(PLC), an application specific integrated circuit (ASIC), and other
programmable circuits, and these terms are used interchangeably
herein. In the embodiments described herein, memory may include,
but is not limited to, a computer-readable medium, such as a random
access memory (RAM), and a computer-readable non-volatile medium,
such as flash memory. Alternatively, a floppy disk, a compact
disc--read only memory (CD-ROM), a magneto-optical disk (MOD),
and/or a digital versatile disc (DVD) may also be used. Also, in
the embodiments described herein, additional input channels may be,
but are not limited to, computer peripherals associated with an
operator interface such as a mouse and a keyboard. Alternatively,
other computer peripherals may also be used that may include, for
example, but not be limited to, a scanner. Furthermore, in the
exemplary embodiment, additional output channels may include, but
not be limited to, an operator interface monitor.
[0020] Further, as used herein, the terms "software" and "firmware"
are interchangeable, and include any computer program storage in
memory for execution by personal computers, workstations, clients,
and servers.
[0021] As used herein, the term "non-transitory computer-readable
media" is intended to be representative of any tangible
computer-based device implemented in any method or technology for
short-term and long-term storage of information, such as,
computer-readable instructions, data structures, program modules
and sub-modules, or other data in any device. Therefore, the
methods described herein may be encoded as executable instructions
embodied in a tangible, non-transitory, computer readable medium,
including, without limitation, a storage device and a memory
device. Such instructions, when executed by a processor, cause the
processor to perform at least a portion of the methods described
herein. Moreover, as used herein, the term "non-transitory
computer-readable media" includes all tangible, computer-readable
media, including, without limitation, non-transitory computer
storage devices, including, without limitation, volatile and
nonvolatile media, and removable and non-removable media such as a
firmware, physical and virtual storage, CD-ROMs, DVDs, and any
other digital source such as a network or the Internet, as well as
yet to be developed digital means, with the sole exception being a
transitory, propagating signal.
[0022] Furthermore, as used herein, the term "real-time" refers to
at least one of the time of occurrence of the associated events,
the time of measurement and collection of predetermined data, the
time for a computing device (e.g., a processor) to process the
data, and the time of a system response to the events and the
environment. In the embodiments described herein, these activities
and events occur substantially instantaneously.
[0023] As described herein, systems and methods are provided for
reducing the CP length in the upstream transmissions. In an
exemplary embodiment, the present techniques are implemented by a
modem of an RFoG network in an upstream OFDMA transmission. The
RFoG modem and RFoG ONU may, for example, be integrated components
of a single device, or may represent two separate elements of the
system. In some embodiments, the present techniques may be
implemented by an MTS (or other control device within the network)
and are applicable to other types of digital transmission networks
and/or downstream digital transmissions, where desired. The present
embodiments advantageously reduce the CP length between data blocks
in an OFDMA frame at the ONU by (i) generating a primary CP to
proceed the OFDMA frame, and secondary CPs of shorter lengths
before all subsequent data blocks in the frame, or (ii)
transmitting an activation tone to the ONU prior to transmission of
OFDMA frame symbols. In either alternative, shorter CPs may be
implemented between substantially all data blocks of an upstream
OFDMA frame, thereby rendering the upstream transmission
significantly more efficient.
[0024] FIG. 2 is a schematic illustration depicting an exemplary
data structure 200 of an OFDMA frame 202. Data structure 200
depicts a "time slice" of an upstream DOCSIS 3.1 transmission. In
the exemplary embodiment, OFDMA frame 202 includes a plurality of
data blocks 204, and a plurality of secondary CPs 206 between
adjacent data blocks 204. A primary CP 208 precedes OFDMA frame
202, that is, in front of the first of data blocks 204 in time.
[0025] In an exemplary embodiment of data structure 200, primary CP
208 has a length sufficient to allow an RFoG ONU laser to turn-on
(e.g., 1.3 .mu.s according to SCTE 174), but for all subsequent
upstream symbols, CPEs 206 have a shorter length, since the ONU
laser is already on for OFDMA frame 202. By implementing shorter
CPs in between subsequent symbols/data blocks 204 in a burst, a
significant amount of upstream capacity can be regained. That is,
by implementing two different CPs--a "long" primary CP 208 and
short secondary CPs 206--the efficiency of the upstream
transmission is significantly increased.
[0026] As illustrated in FIG. 2, data structure 200 thus represents
a modification to the DOCSIS 3.1 specification that presently
provides for a single CP in the upstream transmission for all
symbols. According to this embodiment, the "single" upstream CP
(e.g., secondary CP 206) may be significantly shortened by
providing an additional, longer CP (e.g., primary CP 208) in front
of the OFDMA frame. In at least one embodiment, primary CP 208 is
not necessarily a different CP from secondary CP 206, but instead
may represent two or more instances of secondary CP 206 immediately
adjacent one another. This embodiment is of particular advantageous
use in RFoG networks, where the most significant limitation on the
length of the CP will be experienced prior to the first data block
of an OFDMA frame.
[0027] This embodiment will nevertheless have some additional
usefulness in an HFC network where the CP length needed to
accommodate micro-reflections is less than 1.3 .mu.s. As described
above, the CP for HFC networks are constant. On the HFC network,
the CP primarily functions as a guard time (or "dead time") in
between symbols/blocks to allow the dominant micro-reflection to
die out so that micro-reflection will not interfere with the next
symbol. RFoG does not experience the micro-reflections of HFC, and
thus the RFoG CP (primarily to activate the ONU laser) is used for
different purposes then the HFC CP. Nevertheless, the present
techniques contemplate dominant micro-reflections having durations
shorter than the time needed to activate the ONU laser.
[0028] This dual-CP technique addresses a different problem than
the variable-length CP proposals for a conventional Ethernet
Passive Optical Network (EPON) protocols and an EPON protocol
implemented over coax (EPoC), which utilizes one CP for device
registration, and a different CP for regular data transfer. These
conventional proposals do not contemplate using a different CP
before an OFDMA frame than the CPs between symbols/blocks of the
frame. The embodiment depicted in FIG. 2 is a further particular
value to cable operators running DOCSIS 3.1 upstream over RFoG,
which is becoming more common as operators are building FTTH for
Greenfield construction, but are presently required to run RFoG
over these fibers. Data structure 200 may be implemented by a modem
or modem portion of the ONU at the customer premises (or by a
processor thereof), or alternatively may be controlled by the
MTS.
[0029] FIG. 3 is a schematic illustration depicting an exemplary
data structure 300 of an OFDMA frame 302. Similar to data structure
200, FIG. 2, data structure 300 also depicts a "time slice" of an
upstream DOC SIS 3.1 transmission, and OFDMA frame 302 similarly
includes a plurality of data blocks 304, a plurality of secondary
CPs 306 between adjacent data blocks 304, and a primary CP 308
preceding OFDMA frame 302 in time. Data structure 300 differs from
data structure 200, however, in that primary CP 308 and secondary
CPs 306 may be of the same length. In the exemplary embodiment,
where primary CP 308 has the same length as secondary CP 306, the
modem is configured to transmit a continuous wave (CW) tone 310 to
activate the RFoG ONU laser prior to transmitting the symbols/data
blocks 304 of OFDMA frame 302.
[0030] That is, in exemplary utilization of data structure 300, the
modem is configured to activate the RFoG ONU (i.e., by CW tone 310)
before the modem begins transmitting customer data. Accordingly,
systems and methods according to the embodiment depicted in FIG. 3
achieve even greater versatility in the case where CPs of two
different lengths our impractical, or not allowed. In such cases,
data structure 300 will generally resemble existing single-length
CP OFDMA structures, however, the length of the single CPs in data
structure 300 will be significantly shorter than that of the
conventional OFDMA structures. This shorter CP structure is
achieved by the preceding activation of the RFoG ONU by CW tone
310, which advantageously allows significantly more throughput on
the upstream transmission.
[0031] In the exemplary embodiment, CW tone 310 is generated at the
modem through modification to the DOCSIS MAC layer of that modem,
which may be accomplished through hardware or software. In at least
one embodiment, the DOCSIS MAC layer of the MTS is modified, and
the MTS instructs the modem to transmit CW tone 310 to the RFoG ONU
prior to upstream transmission of customer data, and before symbols
were sent into an OFDMA frame. In an embodiment, CW tone 310 is
optimized to transmit at a specific frequency in the return band,
and/or a specific desired power level. As described above, these
embodiments are of particular use for upstream OFDMA transmissions
of customer data, however, the person of ordinary skill in the art
will understand how the present techniques may be implemented in
downstream transmissions as well, or in other digital transmissions
that utilize CPs between data blocks/symbols.
[0032] The embodiments herein are described above with respect to
optical, FTTH, HFC, RFoG, and conventional cable communication
networks. These several types of communications systems are
discussed by way of example, and are not intended to be limiting.
Other types of communication networks and systems are contemplated
herein without departing from the scope of the invention. Different
protocols for these networks may implement different components to
perform similar functions. For example, a headend or hub of the
network may utilize an Optical Network Terminal (ONT) or an Optical
Line Termination (OLT), and/or an ONU, and one or more optical
protocols including without limitation EPON, RFoG, or GPON. Other
embodiments that are contemplated include communication systems
capable of x-hauling traffic, as well as satellite operator
communication systems, Wi-Fi networks, MIMO communication systems,
microwave communication systems, short and long haul coherent optic
systems, etc. X-hauling is defined herein as any one of or a
combination of front-hauling, backhauling, and mid-hauling.
[0033] For the embodiments described above, the MTS described above
may be substituted with, or additionally include, a termination
unit such as an ONT, an OLT, a Network Termination Unit, a
Satellite Termination Unit, a cable modem termination system
(CMTS), and/or other termination systems which may be collectively
referred to herein as "Modem Termination Systems." Similarly, the
modem described above may be substituted with, or additionally
include, a cable modem (CM), a satellite modem, an Optical Network
Unit (ONU), a DSL unit, etc., which are collectively referred to as
"modems." Furthermore, the DOC SIS protocol may be substituted
with, or further include protocols such as EPON, RFoG, GPON,
Satellite Internet Protocol, without departing from the scope of
the embodiments herein.
[0034] Exemplary embodiments of systems and methods utilizing
dual-CPs and reduced-length CPs are described above in detail. The
systems and methods of this disclosure though, are not limited to
only the specific embodiments described herein, but rather, the
components and/or steps of their implementation may be utilized
independently and separately from other components and/or steps
described herein.
[0035] Although specific features of various embodiments may be
shown in some drawings and not in others, this is for convenience
only. In accordance with the principles of the systems and methods
described herein, any feature of a drawing may be referenced or
claimed in combination with any feature of any other drawing.
[0036] Some embodiments involve the use of one or more electronic
or computing devices. Such devices typically include a processor,
processing device, or controller, such as a general purpose central
processing unit (CPU), a graphics processing unit (GPU), a
microcontroller, a reduced instruction set computer (RISC)
processor, an application specific integrated circuit (ASIC), a
programmable logic circuit (PLC), a programmable logic unit (PLU),
a field programmable gate array (FPGA), a digital signal processing
(DSP) device, and/or any other circuit or processing device capable
of executing the functions described herein. The methods described
herein may be encoded as executable instructions embodied in a
computer readable medium, including, without limitation, a storage
device and/or a memory device. Such instructions, when executed by
a processing device, cause the processing device to perform at
least a portion of the methods described herein. The above examples
are exemplary only, and thus are not intended to limit in any way
the definition and/or meaning of the term processor and processing
device.
[0037] This written description uses examples to disclose the
embodiments, including the best mode, and also to enable any person
skilled in the art to practice the embodiments, including making
and using any devices or systems and performing any incorporated
methods. The patentable scope of the disclosure is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal language of the claims.
* * * * *